A liquid chromatograph is an analysis apparatus in which: a mobile phase (also called eluent) of a liquid and a sample injected into the mobile phase are pressurized by a pump or the like to be caused to pass through a column; and components in the sample are separated and detected based on a difference in interaction (such as adsorption, distribution, ion exchange, and size exclusion) between a stationary phase (also called filler) and the mobile phase in the column.
In the liquid chromatograph, a sample is analyzed under various conditions, in some cases, in order to find the best analysis conditions for the sample (hereinafter, this operation is called method scouting). In the method scouting, the kind of mobile phase, the kind of column, the flow rate of a pump, the temperature of a column oven for heating the column, and the like are set as parameters. Hence, the liquid chromatograph that performs the method scouting is capable of switching these parameters (see Patent Literature 1).
An example of the liquid chromatograph as described above is illustrated in FIG. 4. A liquid chromatograph 1 of FIG. 4 includes a liquid-sending section 10, an auto-sampler 20, a column oven 30, a detection section 40, a system controller 50 for controlling each of these sections, and a control system 60 for managing analysis operations through the system controller 50 and processing data obtained by the detection section 40. An operation section 71 including a keyboard and a mouse, and a display section 72 including a display unit are connected to the control system 60. A plurality of columns 32a to 32f are provided in the column oven 30, and the plurality of columns 32a to 32f are switched by passage-switching sections 31 and 33. In the liquid-sending section 10, solvent containers 11a to 11d and 12a to 12d in which various mobile phases are contained are respectively connected to liquid-sending pumps PA and PB through deaerators 13 and 14 and solvent-switching valves 15 and 16. Examples of the used mobile phases include: aqueous solvents such as water and aqueous solutions obtained by adding various salts to water; and organic solvents such as methanol, acetonitrile and hexane. An aqueous solvent drawn from one of the solvent containers 11a to 11d and an organic solvent drawn from one of the solvent containers 12a to 12d are mixed with each other by a gradient mixer 17 as needed, whereby a mobile phase having a predetermined composition is prepared.
The mobile phase having the predetermined composition that is prepared by the liquid-sending section 10 passes through the auto-sampler 20 to flow into one of the plurality of columns 32a to 32f in the column oven 30. Before that, a sample is injected into the mobile phase by the auto-sampler 20, and the sample passes through the column while being carried by the flow of the mobile phase. In the process, components in the sample are temporally separated and sequentially detected by the detection section 40 provided with a detector 41 such as a photodiode array (PDA) detector.
A number of analyses under various analysis conditions are controlled by the control system 60 embodied by a computer, and are automatically processed. The various analysis conditions are described in a file called “method file”, which is managed by an analysis condition setter 62 in the control system 60, and is stored in a memory 61 in the control system 60. Here, an analysis condition means a combination of parameters (such as the kind of mobile phase, the kind of column, the flow rate of a pump, and the temperature of a column oven that are used in analysis) for controlling operations of the sections constituting the chromatograph. A schedule table creator 63 in the control system 60 creates a file of data called a “schedule table” which is a table describing which analysis conditions are executed in which order. In the schedule table, a sample to be analyzed and an analysis condition for the sample are described in a row, and a series of rows are listed in the columnar direction as analysis time series. A method file is cited as the analysis condition. According to the schedule table, an analysis controller 64 in the control system 60 controls each section in the liquid chromatograph 1 such that a series of analyses are executed under the analysis conditions at predetermined timing. A data processor 65 in the control system 60 acquires an analysis result under each analysis condition and performs processes such as chromatogram creation.